The purpose of the proposed research is to examine the role of social stimuli in coordinating reproductive functions in rodents. This goal is approached in two ways. First by examining the role of social stimuli on the developmnet of sexual maturity and second by examining the role of social stimuli in modifying the adult reproductive state. A social stimulus in the form of a male pheromone markedly accelerates female sexual maturation in mice. This pheromone occurs in a proteinaceous fraction of male urine and additional research is necessary to isolate the substance in pure form. Such purification will (a) yield the first mammalian priming pheromone, (b) permit detailed studies of its physiological and behavioral effects, and (c) provide a tool for examining the physiological basis of puberty. BIBLIOGRAPHIC REFERENCES: Vandenbergh, J.G. 1976. Hormones and aggressive behavior of male hamsters. In: Experimental Psychobiology: A Laboratory Manual, B.L. Hart, ed., Freeman Press, pp. 49-53. Vandenbergh, J.G. and L.C. Drickamer. 1976. Flank gland size and social status in the hamster. In: Experimental Psychobiology: A Laboratory Manual, B.L. Hart, ed., Freeman Press. Pp. 54-57.